Re: [PATCH] irqchip/irq-bcm7038-l1: Prefer struct_size over open coded arithmetic

From: Kees Cook <keescook@chromium.org>
To: Erick Archer <erick.archer@gmx.com>
Cc: Florian Fainelli <florian.fainelli@broadcom.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	"Gustavo A. R. Silva" <gustavoars@kernel.org>,
	linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org,
	Broadcom internal kernel review list
	<bcm-kernel-feedback-list@broadcom.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-hardening@vger.kernel.org
Subject: Re: [PATCH] irqchip/irq-bcm7038-l1: Prefer struct_size over open coded arithmetic
Date: Fri, 9 Feb 2024 16:20:11 -0800	[thread overview]
Message-ID: <202402091620.006E59FF9@keescook> (raw)
In-Reply-To: <20240209183128.10273-1-erick.archer@gmx.com>

On Fri, Feb 09, 2024 at 07:31:28PM +0100, Erick Archer wrote:
> This is an effort to get rid of all multiplications from allocation
> functions in order to prevent integer overflows [1].
> 
> As the cpu variable is a pointer to "struct bcm7038_l1_cpu" and this
> structure ends in a flexible array:
> 
> struct bcm7038_l1_cpu {
> 	void __iomem	*map_base;
> 	u32		mask_cache[];
> };
> 
> the preferred way in the kernel is to use the struct_size() helper to
> do the arithmetic instead of the argument "size + count * size" in the
> kzalloc() function.
> 
> This way, the code is more readable and more safer.
> 
> Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments [1]
> Link: https://github.com/KSPP/linux/issues/162 [2]
> 
> Signed-off-by: Erick Archer <erick.archer@gmx.com>

Yeah, looks right to me.

Reviewed-by: Kees Cook <keescook@chromium.org>

-- 
Kees Cook